PFRPG Defensive Cast extension

I've automated casting defensively to a point in this extension. It will roll a concentration check as the same time as any other rolls needed when the cast button is clicked (such as save rolls or attack rolls). It won't however currently roll vs a DC or come before any of the other rolls and possibly stop them (that's a future update). I added a Cast Defense modifier button to the modifier panel and made sure to maintain compatibility with Kel's Full Overlay, and dogfisc's Combat Modifier Calculation Extension (his buttons will still show up in the right spots if these are used together).

This is also available to look at via github - FG-PFRPG-Defensive-Cast

1st ed gets sweeter every day. thank you :)